DEVELOPMENT, REPRODUCTION, AND PATHOGENICITY OF STEINERNEMA-SCAPTERISCI IN MONOXENIC CULTURE WITH DIFFERENT SPECIES OF BACTERIA

Associations between steinernematid nematodes and their symbiotic bacteria are of fundamental importance. The reported bacterial symbionts of all species of Steinernema are in the genus Xenorhabdus. In this paper, we report on the development, reproduction, and pathogenicity of infective juveniles of Steinernema scapterisci produced on bacteria other than Xenorhabdus spp. The nematode developed and reproduced on a number of bacterial species, including Escherichia coli, Ochrobactrum anthropi, Paracoccus denitrificans, Pseudomonas aureofaciens, Pseudomonas fluorescens Biovar B, Xanthomonas maltophilia, Xenorhabdus nematophilus, and Xenorhabdus spp. Although adult development occurred on all bacterial species, progeny production after 14 days was significantly greater on X. nematophilus and P. fluorescens Biovar B than on the other bacterial species. Infective juveniles which were produced on O. anthropi, P. denitrificans, P. aureofaciens, and X. nematophilus caused equal mortality to the southern mole cricket, Scapteriscus borellii. Since Xenorhabdus spp. is reported to change from a primary phase to a secondary phase with reproduction being considerably less on the secondary phase, and since the nematodes were equally pathogenic when produced on other bacteria, it may be more efficient to produce the nematode on bacteria other than Xenorhabdus rather than contend with phase variation. © 1993 Academic Press, Inc.